The invention relates to cavity trays, that is pre-formed units that are used in buildings generally to bridge a gap in a cavity wall at, for instance, a stop end or change of level.
Such cavity trays are usually made from sheet material which is a combination of synthetic rubbers and thermoplastic polymer resins. The trays are intended to facilitate the damp-proofing of awkward junctions and avoid leakage paths, particularly where they are to be combined with a damp-proof course (DPC). The trays and DPC are usually bonded together using adhesive. The problem is that the trays usually have corners or nooks in which it is virtually impossible to lay a damp-proof course, however flexible that course is. The damp-proof course extends from one level to another leaving an unfilled space between it and the cavity tray along which water can pass so that the inner skin of the wall can become damaged.
It is accordingly an object of the invention to seek to mitigate this disadvantage.
According to one aspect of the invention there is provided a cavity tray for use in a cavity wall, comprising two spaced apart flanges each adapted in use to lie in or adjacent a respective skin of the wall, a connector connecting the two spaced apart flanges, and an arcuate transitional part leading to at least one flange whereby a super- or sub- posed damp-proof member may be adhered thereto with substantially no discontinuity.
The arcuate part is in use adapted to obviate abrupt changes direction in a direction from one flange to the other.
There may be a transitional part of arcuate configuration between each respective flange and the connector.
The tray may be made integrally in one piece.
One flange may extend in an opposite direction to the other and there may be a member extending at substantially 90.degree. to the plane of the connector and the one flange.
One flange may extend in a direction of substantially 90.degree. to the direction of the other flange, and there may be a member extending at substantially 90.degree. to the plane of the connector and the one flange.
The member may terminate short of the arcuate part adjacent the other flange.
The tray may include a further flange extending a substantially 90.degree. to the plane of the other flange to form therewith an "L"-configuration.
The one flange and the connector at least may be in two parts one of which is stepped with respect to the other, and the two parts may be connected by an integral wall member.
The other flange may be in two parts one of which may be stepped with respect to the other, the two parts being connected by the integral wall member.
The tray may comprise separate components secured together to form an integral unit by a high frequency welding process.
The tray may be integrally formed by injection moulding, or by vacuum forming.
The cavity tray may be formed from a mouldable composition comprising synthetic rubber and a thermoplastic polymer resin, which may comprise a fibre content.
According to a second aspect of the invention, there may be provided a damp-proof system of a structure, comprising a cavity wall, a damp-proof course extending across the cavity from the inner skin to the outer skin over a particular length, and a cavity tray as hereinbefore defined at at least one end of the length of damp-proof course whereby to obviate end leakage of moisture to the skin(s) of the wall.
There may be a cavity tray according to any of claims 1 to 15 at each end of the particular length of damp-proof course.